A number of seat liners for strollers, car seats, stroller bassinets, and high chairs have been known in the art for decades. However, there are a number of known unresolved problems with vinyl and synthetic canvas (harsh, polyester, nylon or neoprene) materials from which the stroller upholstery is typically made. Vinyl is hot and sticky in the summer and cold and stiff in winter. Vinyl, canvas and nylon may be rough on delicate skin and do not offer an acceptable level of comfort for children. Also, such materials are difficult to keep clean as they are typically impossible to remove as they are usually permanently attached to the stroller, car, seat, high chair, etc. Moreover, currently used inserts in strollers do not absorb shock or reduce the effect of traveling over rough ground. Therefore, there is a need for a comfortable and versatile seat liner for strollers, stroller bassinets, car seats and high chairs which would address all aforementioned issues and provide its users with benefits of esthetic appeal, help to keep strollers clean and looking new, provide adequate cushioning to absorb shock, reduce musculoskeletal stress and support proper anatomical development in children.